In contrast to a common sand casting method, several methods have been proposed to produce a casting with excellent dimensional accuracy. For example, the investment casting method (also called as lost-wax method), the plaster mold casting method, and the evaporative pattern casting method have been developed.
Among those methods, the evaporative pattern casting method is considered as the most suitable method to form a hole inside a casting by casting (this formation is referred to as “hole casting”). The evaporative pattern casting method is a method for producing a casting by burying into casting sand a mold, which is formed by application of a coating agent to the surface of a foam pattern, and then pouring a metal melt into the mold to cause the foam pattern to disappear and be replaced with the melt.
JP 2011-110577 A discloses an evaporative pattern casting method to set casting time during casting in accordance with a pattern modulus (a pattern volume divided by a pattern surface area).